Those Russian soldiers who stay in Syria will be engaged in monitoring the ceasefire regime, Putin said.

Pavel Felgenhauer, a Russia defence analyst, said Russia is seeking a compromise with the West.

"This is Russia's air force that is in action," he told Al Jazeera from Bucharest, Romania.

Marwan Bishara: The meaning of Putin's Syria surprise

"This doesn't mean that Russia is withdrawing from Syria or abandoning the Assad regime. But it does mean Russia is seeking a compromise... Russia is absolutely not ready to take on the West over Syria."

Earlier on Monday, after talks resumed in Geneva to end the conflict, Syria's top government negotiator described as "positive and constructive" his meeting with Staffan de Mistura, the UN special envoy for Syria.

Bashar Jaafari, Syria's ambassador to the UN, said his government was interested in a dialogue that is "Syrian-led without foreign intervention and precondition".

For his part, Salim al-Muslet, of the opposition High Negotiations Committee (HNC), said his side was also "optimistic", but he insisted on a "political transition" in Syria "without Assad."

"I believe that there are positive points that we can count on," he told Al Jazeera from Geneva. "We are keen to find a solution that would end the suffering of the Syrians. For Assad to be in power is not acceptable."

The Syrian conflict has killed more than 250,000 people and displaced almost half the country's pre-war population of 23 million.

A fragile ceasefire has largely held since February 27, and humanitarian aid deliveries have resumed in recent weeks.